1. Field of the Invention
This invention relates to a method and apparatus for applying indicia such as designs, letters, numbers and/or words on substrates. Particularly, the invention relates to a method and apparatus for directly printing indicia in the form of designs, letters, numbers and/or words, for example, on caps, hats, T-shirts and the like for identification, information, promotion, and/or aesthetic purposes but is not limited to any specific indicia or type of substrate. More particularly, the invention relates to printing such designs, letters and/or words on substrates with the use of a curved screen and apparatus which incorporates a curved screen.
2. Description of the Prior Art
For many, many years indicia in the form of, for example, designs, letters, numbers and/or words have been applied to substrates for purposes of identification, information, promotion, or aesthetic purposes. Such substrates especially included hats, caps, T-shirts and other articles of clothing whereby the wearer could identify or be identified with a particular group, cause, club and the like. In addition, logos have been printed on caps or hats for purposes of advertising or information. Similarly, an infinite number of designs have been applied to articles of clothing for aesthetic, informational or other purposes.
Early processes and apparatus for printing and dyeing fabrics are disclosed in U.S. Pat. Nos. 576,623 and 798,528.
Although the usual techniques for applying such indicia to substrates were somewhat elementary, for example, the use of stencils on containers or the like, or heat transfers for articles of clothing, the wide acceptance of indicia on clothing articles has prompted persons in the art to search for better methods and apparatus for applying indicia to clothing articles so that the detail of the designs is maintained and the design on the articles presents a professional appearance.
Various techniques which have been used include the process and apparatus disclosed in U.S. Pat. No. 3,745,970 wherein a diaphragm carrying a pattern is forced by air into engagement with a plate for coating an article, and portable stenciling apparatus using a process as described in U.S. Pat. Nos. 4,048,918 and 4,164,183.
The attempt to obtain expert design in detail is complicated by the fact that some of the surfaces to be printed are curved or at least not perfectly planar. Special apparatus has been designed for printing such curved or irregular surfaces, such as that described in U.S. Pat. No. 4,314,503. This is particularly true in the case of hats or caps where printing of the indicia on the head band is required after the hat is manufactured.
A recent method and apparatus for printing curved surfaces described in U.S. Pat. No. 4,381,706 comprise a frame having a curved printing screen. The device is designed for printing indicia on caps and hats using a squeegee. Although the method and apparatus described in the patent are said to overcome the difficulties of pattern distortion experienced in the art, there are still pattern distortions with the use of the patented method and apparatus.
The present method and apparatus overcome these deficiencies and produce a non-distorted, detailed image on a substrate, either curved, planar or irregular, such as a cap, hat, T-shirt or the like.